Dual-device backup is a feature that ensures service traffic continuity in scenarios in which a master/backup status negotiation protocol (for example, VRRP or E-Trunk) is deployed. Dual-device backup enables the master device to back up service control data to the backup device in real time. When the master device or the link directly connected to the master device fails, service traffic quickly switches to the backup device. When the master device or the link directly connected to the master device recovers, service traffic switches back to the master device. Therefore, dual-device backup improves service and network reliability.
Unicast dual-device backup for IPv4/IPv6
Unicast dual-device backup for IPv4/IPv6 uses the dual-device backup technology to back up IPoE/PPPoE user information. When the master device or the link, interface, or board of the master device is faulty, services can be quickly switched to the slave device.
Multicast dual-device backup for IPv4
Multicast dual-device backup for IPv4 is based on the dual-device backup for access users.
The multicast dual-device hot backup technology provides high reliability when theNetEngine 8000 F is used as the service control point and multicast replication point. This technology mainly applies to the Interactive Personality TV (IPTV) service scenario.
When deploying the IPTV service, operators use the BRAS as the multicast replication point. Set Top Boxes (STBs) can be classified into Dynamic Host Configuration Protocol (DHCP) STBs and Point-to-Point Protocol over Ethernet (PPPoE) STBs. Hot backup ensures service continuity by allowing the slave BRAS to take over services when the master BRAS is being upgraded or a fault occurs on the user side or network side of the master BRAS.
VRRP is a fault-tolerant protocol that groups several routers into a virtual router. If the next hop of a host is faulty, VRRP switches traffic to another router, which ensures communication continuity and reliability.
For details about VRRP, see the chapter "VRRP" in NetEngine 8000 F Feature Description - Network Reliability.
RUI is a Huawei-specific redundancy protocol that is used to back up user information between devices. RUI, which is carried over the Transmission Control Protocol (TCP), specifies which user information can be transmitted between devices and the format and amount of user information to be transmitted.
The remote backup service (RBS) is an RUI module used for inter-device backup. A service module uses the RBS to synchronize service control data from the master device to the backup device. When a master/backup VRRP switchover occurs, service traffic quickly switches to a new master device.
The remote backup profile (RBP) is a configuration template that provides a unified user interface for dual-device backup configurations.
E-Trunk implements inter-device link aggregation, providing device-level reliability. E-Trunk aggregates data links of multiple devices to form a link aggregation group (LAG). If a link or device fails, services are automatically switched to the other available links or devices in the E-Trunk, improving link and device-level reliability.
For details about E-Trunk, see "E-Trunk" in NetEngine 8000 F Feature Description - LAN Access and MAN Access.
In traditional service scenarios, all users use a single device to access a network. Once the device or the link directly connected to the device fails, all user services are interrupted, and the service recovery time is uncertain. To resolve this issue, deploy dual-device backup to enable the master device to back up service control data to the backup device in real time.
Benefits to users
The dual-device backup for user access improves network reliability. When the network is faulty, the slave BRAS can quickly take over user services. And in this case, users can use network resources continuously without realizing the network failure.
Benefits to operators
Improving network reliability from the perspective of service reliability.